The parenteral administration, including intravenous administration of beneficial fluids is commonly used in clinical practice. Presently, beneficial drugs also are administered by using a parenteral delivery system. The parenteral system used for administering the beneficial drug generally consists of a reservoir that contains a premixed formulation consisting essentially of the beneficial drug and a parenterally administrable fluid. The premixed formulation is administered by gravitational flow by suspending the reservoir above the patient.
While this form of parenteral administration is widely used and often leads to successful therapy, there is still a great deal of clinical dissatisfaction with the chemotherapy of parenteral delivery systems. For example, the parenteral system frequently overdoses, or it underdoses outside of the therapeutically effective range, the parenteral system does not permit exact dosing of the medicament, and the parenteral delivery system is not programmable for delivering a drug according to the needs of a patient.